Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, touch sensor panels, joysticks, touch screens and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which may be a clear panel with a touch-sensitive surface. The touch sensor panel can be positioned in front of a display screen so that the touch-sensitive surface covers the viewable area of the display screen. Touch screens can allow a user to make selections and move a cursor by simply touching the display screen via a finger or stylus. In general, the touch screen can recognize the touch and position of the touch on the display screen, and the computing system can interpret the touch and thereafter perform an action based on the touch event.
One limitation of touch sensor panel technologies is that noise can adversely affect the performance of a touch sensor panel device. Noise from sources such as a power adapter can influence the results of a touch sensor panel device. For example, the touch sensor panel device can be coupled to a power adapter to charge a battery of the device. The power adapter can introduce noise while charging, which may prevent a touch sensor panel from distinguishing between a touch event (e.g., a user's contact of a touch sensor panel) and noise influencing the sensors of the touch sensor panel.